Tobacco smoke filter

ABSTRACT

A tobacco smoke filter and in particular a cigarette filter is disclosed which comprises an absorbent non-tobacco filter support which carries an impregnation of a hydrocarbon constituted of a normal paraffin having 11 to 18 carbon atoms in the molecular chain. The normal paraffin has the general formula CNH2N 2 and constitutes approximately 1 to 12 percent by weight of the fitter. The hydrocarbon is liquid at ambient temperature and has a vapor pressure not substantially in excess of one millimeter Hg at ambient temperature. The hydrocarbon impregnation may include also a normal paraffin having more than 18 carbon atoms in the molecular chain. The paraffin mixture is likewise liquid.

United States Patent Martin [151 3,654,934 [4 1 Apr. 11, 1972 [54] TOBACCO SMOKE FILTER [72] Inventor: Joseph F. Martin, Painesville, Ohio [73] Assignees: Joseph F. Martin; Marmanac Inc., Cleveland, Ohio; Chemfilt Corp. of America, North Tarrytown, NY. part interest to each [22] Filed: Oct. 8, 1969 [21] Appl. No.: 864,761

Related U.S. Application Data [62] Division of Ser. No. 613,351, Feb. 1, 1967, Pat. No.

[52] U.S. Cl ..13l/267, 131/17 [51] Int. Cl. ..A24b 15/02 [58] Field ofSearch ..l31/l7, 261-269,

[56] References Cited UNITED STATES PATENTS 2,158,565 5/1939 Andrews ..131/l7R 2,992,648 8/1961 Weiss ..131/267X FOREIGN PATENTS OR APPLICATIONS 173,262 12/1952 Austria ..l31/l0 OTHER PUBLICATIONS The Dispensatory of the U.S. of America" (Text) Osol-Farrar, .I. B. Lippincott Co., Phila., Pa. 25 Edition, p. 1024 & 1025 Primary Examiner-Melvin D. Rein Attorney-Team, Teare & Sammon [5 7] ABSTRACT A tobacco smoke filter and in particular a cigarette filter is disclosed which comprises an absorbent non-tobacco filter support which carries an impregnation of a hydrocarbon constituted of a normal paraffin having 11 to 18 carbon atoms in the molecular chain. The normal paraffin has the general formula C H and constitutes approximately 1 to 12 percent by weight of the fitter. The hydrocarbon is liquid at ambient temperature and has a vapor pressure not substantially in ex cess of one millimeter Hg at ambient temperature. The hydrocarbon impregnation may include also a normal paraffin having more than 18 carbon atoms in the molecular chain. The paraffin mixture is likewise liquid.

9 Claims, 5 Drawing Figures PATENTEDAPR 1 1 I972 SHEET 1 OF 2 INVENTOR.

JOSEPH F. MARTIN BY {1444- (M ATTORNEYS PATIENTEDAPR 11 me 3,654,934

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INVENTOR. 5 I JOSEPH F MARTIN ATTORNEYS TOBACCO SMOKE FILTER This application is a division of the co-pending application to Joseph F. Martin, Ser. No. 613,351 filed Feb. 1, 1967, now US. Pat. No. 3,490,462.

BACKGROUND OF THE INVENTION The present invention relates to the treatment of gaseous media, and more particularly relates to the treatment of tobacco smoke and to the treatment of tobacco smoke filter material. In particular it relates to the treatment of filters for cigarettes, cigars, pipes or the like or holders therefor and to materials for reducing the benzo-(a)-pyrene from the gaseous media and to provide a smooth, mild taste thereof.

Previous studies, including the Report of the Advisory Committee to the Surgeon General of the Public Health Service- Publication No. l 103-have discussed the harmful effects of smoking, particularly in relation to cigarettes. Such studies have established that certain chemical compounds are cancer producing (carcinogenic). Most of the carcinogenic compounds identified in cigarette smoke tar are not present in the native tobacco leaf, but are formed by pyrolysis at the high burning temperature of the cigarette material. At least seven polycylic hydrocarbons which are also carcinogens have been identified in tobacco smoke. Examples of strongly carcinogenic compounds of this type include benzo-(a)-pyrene, dibenzo (a,i) pyrene and dibenzo (a,h) anthracene. Benzo- (a)pyrene is by far one of the most potent of the strongly noted carcinogens detected in tobacco smoke and is present in a much larger quantity as compared to any of the other carcinogenic compounds.

The species Nicotina tabacum is now the chief source of smoking tobacco cultivated in the United States. The present invention, however, relates to any type of tobacco. The tobacco leaf contains a complex mixture of chemical substances, such as cellulosic products, starches, proteins, hydrocarbons, etc. The smoke of a cigarette is a heterogeneous mixture of gases, uncondensed vapors and liquid particulate matter. As the smoke enters the mouth it is a concentrated aerosol with millions or billions of particles per cubic centimeter. The size of the particles of the aerosol range is from less than 0.1 microns to about 5 microns; and are counted in the billions per cubic centimeter of smoke. When tobacco is smoked, and the smoke condensed or otherwise collected, the condensate, known as tobacco tars, contains the particulate phase of the smoke, and most of the easily condensable components of the gas phase. The reported amount of tar from the smoke of one cigarette is between about 3 and 40 mg., the quantity varying according to the burning and condensing conditions, the length of the cigarette, the use of a filter, porosity of paper, content of tobacco, weight and kind of tobacco employed. While air is being drawn through the cigarette the temperature of the burning zone reaches approximately 884 C. and when the cigarette is burning without air being drawn through it the temperature is approximately 835 C. At the temperatures cited, extensive pyrolytic reactions occur in the tobacco to produce the aforementioned carcinogenic effects in the tobacco smoke.

Examples of the types of pyrolsis which contribute to the contamination of air with carcinogens include industrial processes such as the destructive distillation of coal and wood, smoking of food products such as meats, burning of fuel in a diesel or gasoline engine, incineration of trash, and probably most important from the aspect of lung cancer, the pyrolysis of tobacco during smoking.

While the present invention has applicability to the treatment of any gas stream containing carcinogenic hydrocarbons, it will be described most particularly with respect to tobacco smoke.

It has been found that generally one cigarette will produce about 20 to 30 mg. of tars while 1,000 cigarettes will produce about 38 micrograms of benzo-(a)-pyrene. It has further been determined that heme-(a)pyrene constitutes about 90 percent of all of the cancer-producing ingredients in the tars and has a potency of about 10,000 as compared to most of the other carcinogens in the tars. Moreover, if the benzo-(a)- pyrene content of the smoke can be substantially reduced, then the total carcinogenic property of the smoke can also be effectively reduced.

In accordance with the present invention, there is provided a control for the aforementioned carcinogenic substances which contemplates incorporating with the tobacco smoke filter materials, a liquid n-paraffin in an amount sufficient to reduce the carcinogenic content of the smoke, and to improve the taste thereof.

The foregoing objects, as well as others, will become apparent from the following description in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view partially in section showing a cigarette made in accordance with the invention;

FIG. 2 is a perspective view partially in section showing a filter for use with a cigarette or the like made in accordance with the invention;

FIG. 3 is a perspective view partially in section showing the filter as in FIG. 2 made integral with a cigarette as in FIG. 1;

FIG. 4 is a perspective view partially in section showing a holder for cigarettes, cigars or the like made in accordance with the invention; and

FIG. 5 is a graphic illustration showing certain of the physical and chemical properties of the selective range of the nparaffins used in accordance with the invention.

SUMMARY OF THE INVENTION In general, the foregoing objects and other related advantages are achieved in accordance with the present invention by treating a smoking mixture in one form, such as tobacco, with a control substance in the class of saturated hydrocarbon paraffins. Preferably, a liquid, straight or continuous chain hydrocarbon, such as the normal (n) paraffins, are used in an amount sufficient to substantially reduce the benzo-(a)- pyrene content of the smoke. When treating a smoking mixture, such as tobacco, the n-paraffin is present in the range from about 0.1 to 3 percent, based on the weight of the tobacco. Below 0.1 percent the effect is somewhat diminished, and about 2.5 percent the tobacco becomes oily in nature. Preferably, the range is from about 0.1 to 1.6 percent, based on the weight of the tobacco. In treating a substance, such as a filter material, the n-paraffin is preferably present in the range from about 1.0 to 12 percent, based on the weight of the filter material. Good results are achieved with about 4 percent of the n-paraffin.

DESCRIPTION OF PREFERRED EMBODIMENTS The practice of the invention may be illustrated by the following examples without, however, being considered as limited thereto.

EXAMPLE A A mixture of heavy fraction n-paraflins, such as dodecane about 13 percent, tridecane about 49.7 percent, tetradecane about 37 percent, pentadecane etc. about 2 percent, was subjected to distillation until the boiling point of the material in the still rose to about 218 C. About 3 percent of the original weight was removed. The material left in the still was virtually odorless. Then 3.6 grams of the mixture was mixed with .10 grams of water and a trace of dispersing agents IGEPAL CO-430 and CO-850. In each case, the amount used was less than 0.005 grams. The mixture was shaken and a white emulsion resulted which remained stable for 30 minutes.

EXAMPLE I One pound of shredded tobacco, identical to that used in making commercial cigarettes, was sprayed with 13.6 grams of the n-paraffin-water emulsion described in Example A" above. The tobacco was then mixed, by tumbling, in a gas tight tumbler for 30 minutes. The tobacco was then made into cigarettes on a small commercial machine, using approximately 1 gram of tobacco per cigarette. The cigarettes were 68 mm. long. Several hundred such cigarettes, and several hundred made in an identical manner, but without treating the tobacco, were aged for 72 hours at 70 F. and 60 percent relative humidity, then smoked in a smoking machine built by Byrd & Phipps of Richmond, Va.

The cigarettes were all smoked to butt length of 18 mm. and the tars collected on Cambridge filters, using one filter per eight cigarettes. The smoking cycle was 30 seconds, with 2 seconds draw and 2 seconds discharge. The column drawn at each puff was 35 ml. Each cigarette yielded from nine to 10 uffs. p The tars were analyzed for benzo-(a)-pyrene with the Davis, Lee & Davison method. The untreated cigarettes yielded tars containing 20 micrograms of benzo-(a)-pyrene per 1,000 cigarettes, while the treated cigarettes yielded only 5 micrograms per 1,000 cigarettes, or a reduction of 82 percent in benzo-(a)-pyrene.

EXAMPLE II Example I above was repeated, except that the light fraction of the n-paraffins, such as decane about 12.8 percent, undecane about 40.9 percent, dodecane about 37.5 percent, tridecane 8.5 percent, tetradecane etc. about 2 percent, was used. The light fractions were first subjected to distillation to attain a boiling point of 205 C. By this distillation, most of the decane and all of the odorous branched chain compounds were removed. In this case, the treated cigarettes carrying 3.6 grams of n-paraffins per 1 pound of tobacco, or 0.8 percent, based on the tobacco weight, yielded only 2 micrograms of benzo-(a)-pyrene per 1,000 cigarettes giving a reduction of more than 93 percent in benzo-(a)-pyrene.

EXAMPLE III 100 commercial cigarettes were smoked and the tars collected as in Example I above. The yield of benzo-(a)-pyrene was 2.9 micrograms.

A mixture of 2 parts water, 1 part light n-paraffins, as used in Example II above, was emulsified using a trace of ammonium stearate. A Burette was used which delivered 40 drops of this emulsion per ml. One drop contained approximately 0.008 grams of n-paraffins and 0.016 grams of water. One drop of this solution was dropped in each filter of 100 commercial cigarettes. The cigarettes were wrapped in a plastic container and aged for 3 days during which time the n-paraffins diffused over the surfaces of the filter material. These cigarettes were then smoked and the tars collected as in Example I. The yield of benzo-(a)-pyrene was 0.4 micrograms, showing a reduction in excess of 86 percent.

EXAMPLE IV The filter treatment in Example III above was increased to two drops per filter of 0.016 grams of n-paraffins per filter. The filter material weighted 0.2 grams in all cases. Smoking and collection of the tars was performed as in Example II. The yield of benzo-(a)-pyrene was so small as to make the reading negligible. It was in the order of about 0.1 micrograms, showing a reduction of benzo-(a)-pyrene in excess of 96 percent.

EXAMPLE V Filters, especially made of cellulose acetate and weighing 0.2 grams each were treated with 0.012 grams of n-paraffins by using the method of Example III. These were enclosed in a paper cylinder to provide a cigarette holder, FIG. 4.

100 commercial cigarettes-with an attached filter-and 100 commercial cigarettes-without filters-were smoked and the benzo-(a)-pyrene in the smoke measured. The results: 100 filter tips gave 2.85 micrograms and the 100 without filters gave 2.90 micrograms.

Then the commercial cigarettes were each smoked, except that each cigarette was first placed in a cigarette holder as described above. The benzo-(a)-pyrene in the collected tars was less than 0.1 micrograms in each case, indicating a reduction in excess of 96 percent per both sets of cigarettes when smoked in conjunction with the cigarette holder.

After separation of the benzo-(a)-pyrene in accordance with the method of H. J. Davis, L.A. Lee and T. R. Davidson, of Summit Research Laboratories, Celanese Corporation of America, the instrument used to evaluate the benzo-(a)- pyrene was a Ferrand Spectro fluorimeter. Because this instrument can detect and evaluate a concentration of 0.01 micrograms per ml. of benzo-(a)-pyrene, it is believed that the method of treatment in accordance with Example II produced a substantially complete elimination of benzo-(a)-pyrene.

In accordance with the invention, the n-paraffins are present or applied in the range from 0.1 to 3 percent, based on the weight of the tobacco. Preferredresults are achieved with a range from about 0.1 to 1.6 percent, based on the weight of the tobacco. Similarly, for treating filter material the range is about 1.0 to 12 percent, based on the weight of the filter material. Preferred results achieved with about 4 percent, based on the weight of the filter material.

Suitable flavoring ingredients, humectants, and the like may be admixed with the tobacco and/or with the n-paraffins. For example, the humectant may be present in the amount of 3 percent and moisture present in the amount of 12 to 12% percent based on the weight of the tobacco, when dry. The humectant may be any suitable material, such as glycerin or other polyhydric alcohol, as known in the art. The tobacco to which the n-paraffins are applied may be in a form suitable for direct use in a cigarette or other smoking article for which it is to be applied. For example, a tobacco which has been aged, humected, shredded and treated with other tobacco-treating ingredient may be used, as desired.

Because of the physical problems of thoroughly mixing, such as 0.8 percent of the n-paraffins with tobacco, it is preferred that the n-paraffins be diluted with a diluent. However, prolonged mixing will achieve a homogeneous mixture. This diluent can be water, however, the n-paraffins and water do not easily mix, but the paraffins can easily be emulsified in the water by means well known in the art. Diluents or dispersing agents which may be employed include soaps-the sodium, potassium or ammonium salts of acids, sulphonates, ethylenated alcohols, oxonium compounds, and many others which in one way or another reduce surface tension and cause dispersion. It is preferred that ammonium soaps or ethylenated alcohols be used. The former may include ammonium palmitate and the latter may include IGEPAL CO-430 and 850. The dispersing agent may be mixed either with the n-paraffins or with the water.

The quantity of the dispersing agent may be from about 0.1 to 0.01 percent, based on the weight of the n-paraffins. Preferably, the amount is just sufficient to produce a temporary emulsion. It is to be noted, however, that the diluent may be a volatile and harmless hydrocarbon, such as hexane, or any reasonably volatile and non-toxic organic solvent, such as the alcohols, esters, etc. Moreover, the diluent takes no part in the reaction, but is a transient material employed to distribute the n-paraffin on the tobacco and/or filter material.

The preferred control substance for reducing the carcinogenic effects of the tobacco smoke or smoking articles in accordance with the invention are the normal or n-paraffins (straight chain) which can be defined by the general formula C H2n The hydrocarbon molecules, or the straight chain paraffin materials may be made of carbon chains having carbon atoms in the range from 11 to 20. Preferably, the sslis IQ IL'U o fi'sa sn a suns-l -t i P e e e range, the vapor pressure would be very low at ambient temperature. For example, it has been determined that an n-paraffin with ll carbon atoms produces a vapor pressure of 1 mm. at ambient temperature. Moreover, other such hydrocarbons having a carbon content higher than ll, such as l2, l3, 14, etc., all produce less vapor pressure at room temperature.

Preferably, the vapor pressure of the material is 1 mm. or below. It has also been found that the melting point of the preferred range is such that the hydrocarbon is liquid at ambient temperature. Preferably, the melting point is in the range from minus 265 to 28 C. The boiling point for the preferred range may be between about l95.8 to 317 C. at 760 mm. pressure. Preferably, the boiling point is above 200 C. Reference may be had to FIG. 5 which graphically shows the melting points, boiling points and temperatures at which the n-paraffins develop l mm. of vapor pressure. It has been found that hydrocarbons of this type having in excess of l8 carbon atoms tend to become wax-like at ambient temperature. It has been found, however, that such hydrocarbons may be employed having in excess of 18 carbon atoms when mixed with normal paraffins having carbon atoms in the preferred range from ll to 18 so that the mixture is in the form of a liquid at ambient temperature. It is believed that due to the low vapor pressure of the normal paraffins they have little, if any, odor. Examples of such n-paraffins which may be employed include undecane, dodecane, etc., up to triacontane. In the preferred range, the n-paraffins include undecane up to and including octadecane.

When the n-paraffins are distilled either in air or in steam, most of the odorous branched chain compounds are removed. The residual mixtures of n-paraffins have extremely faint and slightly pleasant odors. The specific mixture of n-paraffins is dependent upon the source of the crude petroleum and the methods used to isolate the n-paraffins. Any mixture of nparaffins containing undecane to octadecane may be used so long as the mixture thereof is liquid at room temperature. Beyond octadecane, the n-paraffins are waxes at ambient temperature. They are useful in the present invention provided they are soluble in the other, lower melting point n-paraffins, at ambient temperature. Thus, other mixtures containing compounds as large as hexacontane C H may be used provided the total composition remains liquid at ambient temperatures. Compounds below undecane exhibit vapor pressures at ambient temperatureswhich would cause them to evaporate slowly and so disappear from sight (i.e., from the tobacco, or filter material) after a short period of time. For example, undecane has such a low vapor pressure at ambient temperatures (70 F 35 C.), that it would be expected to remain on the tobacco, or filter material for a very long period of time, such as 1 year or more.

The invention contemplates the provision of smoking articles. such as cigarettes, filters for cigarettes and holders for cigarettes made from tobacco or other material which are treated with normal paraffins in accordance with the invention. In FIG. 1 there is shown a cigarette 2 which comprises a wrapper 4 of cigarette paper. Inside the wrapper 4 is disposed a quantity of tobacco 6 treated with n-parafins. In FIG. 2 there is shown a filter 8 for a cigarette which can be composed of any non-tobacco absorbent material 10. The absorbent material 10 may be a fibrous and/or granular material, such as cellulose acetate, cotton, porous paper, charcoal, clay, silica or the like as known in the art and treated with the n-paraffins in accordance with the invention. Accordingly, the filter 8 may be made as an integral part of the cigarette of FIG. 1 by being integral with the column of tobacco as seen in FIG. 3, or may be made separate therefrom as seen in FIG. 2. It is to be noted, however, that the filter 8 could also be used in smoking pipes and in cigarette or cigar holders 12 of the type shown in FIG. 4 either as an integral or removable component thereof. As shown, the holder could have a flared end, as at 14, to accommodate variations in cigarette or filter tip cigarette dimensions. It is to be noted that many variations of this type of holder may be employed, such as larger ones for cigars, highly decorated types, and others with very long filter sections.

From the foregoing description and accompanying drawings, it will be seen that in accordance with the present invention that smoking articles treated in accordance with the invention exhibit substantially reduced carcinogen content as compared to commercial non-treated cigarettes and that such tobacco and/or smoking articles have an improved smooth,

pleasant taste.

I claim:

1. In a tobacco smoke filter, an absorbent non-tobacco filter support material of a shape conforming to the smoke passageway of the support carrying an impregnation of a hydrocarbon material, said filter consisting essentially of a normal paraffin having II to 18 carbon atoms in the molecular chain thereof, I

said hydrocarbon material consisting essentially of a straight chain, normal paraffin substance having the general formula x zvn,

said hydrocarbon material disposed on said filter and present in the amount of approximately 1 percent to approximately l2 percent based on the weight of the filter material, and

said hydrocarbon material being liquid at ambient temperature and having a vapor pressure not substantially in excess of I millimeter Hg at ambient temperature.

2. A tobacco smoke filter in accordance with claim 1 wherein said hydrocarbon additionally includes at least one other normal paraffin having more than 18 carbon atoms in the molecular chain thereof, and said entire normal paraffin mixture is liquid at ambient temperature.

3. A filter in accordance with claim 1, wherein said normal paraffin substance has a melting point from minus 26 to 28 C. with a boiling point from 198 to 317 C. at 760 millimeters Hg pressure.

4. A filter in accordance with claim 1, wherein said normal paraffin is in the form of a liquid emulsion distributed in wetting relation on said filter material, and

said emulsion including a diluent and an emulsifying agent.

5. A filter in accordance with claim 4, wherein said diluent is water and said emulsifying agent is ammonium stearate.

6. A filter in accordance with claim 4, wherein said liquid contains a major amount of liquid diluent, a

minor amount of said non'nal paraffin substance, and an emulsifying agent.

7. A filter in accordance with claim 2, wherein said normal paraffin substance has a melting point from minus 26 to 28 C. with a boiling point from 198 to 317 C. at 760 millimeters Hg pressure.

8. A filter in accordance with claim 2, wherein said normal paraffin is the form of a liquid emulsion distributed in wetting relation on said filter material, and

said emulsion including a diluent and an emulsifying agent.

9. A filter in accordance with claim 8, wherein said liquid contains a major amount of liquid diluent, a

minor amount of said normal paraffin substance, and an emulsifying agent. 

2. A tobacco smoke filter in accordance with claim 1 wherein said hydrocarbon additionally includes at least one other normal paraffin having more than 18 carbon atoms in the molecular chain thereof, and said entire normal paraffin mixture is liquid at ambient temperature.
 3. A filter in accordance with claim 1, wherein said normal paraffin substance has a melting point from minus 26* to 28* C. with a boiling point from 198* to 317* C. aT 760 millimeters Hg pressure.
 4. A filter in accordance with claim 1, wherein said normal paraffin is in the form of a liquid emulsion distributed in wetting relation on said filter material, and said emulsion including a diluent and an emulsifying agent.
 5. A filter in accordance with claim 4, wherein said diluent is water and said emulsifying agent is ammonium stearate.
 6. A filter in accordance with claim 4, wherein said liquid contains a major amount of liquid diluent, a minor amount of said normal paraffin substance, and an emulsifying agent.
 7. A filter in accordance with claim 2, wherein said normal paraffin substance has a melting point from minus 26* to 28* C. with a boiling point from 198* to 317* C. at 760 millimeters Hg pressure.
 8. A filter in accordance with claim 2, wherein said normal paraffin is the form of a liquid emulsion distributed in wetting relation on said filter material, and said emulsion including a diluent and an emulsifying agent.
 9. A filter in accordance with claim 8, wherein said liquid contains a major amount of liquid diluent, a minor amount of said normal paraffin substance, and an emulsifying agent. 